1. Field of the Invention
The present invention relates to the art of forming products from particulate materials. More particularly, the present invention relates to the compaction of particulate materials. Still more particularly, the present invention relates to a new tool rig for the compaction of particulate materials.
2. Description of Related Art
In the manufacture of components or parts from particulate materials, a critical process is the compaction of the particulate material. Compaction is typically performed by filling a die cavity with the particulate material and applying pressure to the particulate material with a press.
The press has a driven main ram that moves in a single direction. The main ram is connected to a ram platen that moves with the main ram. In most cases, the main ram and ram platen move in a downward direction toward a base platen to perform the compaction. The main ram may be driven by hydraulic or mechanical means, as known to those skilled in the art. Depending on the operation, additional rams may be present to provide auxiliary motion in a coaxial direction.
For compaction different types of presses may be utilized, among them a hybrid press and a hydraulic press. A hydraulic press includes a hydraulically driven main ram and hydraulic auxiliary motions. A hybrid press comprises a crank or knuckle driven main ram and hydraulic auxiliary motions. Adjustable mechanical stops are used to prevent auxiliary motion beyond the desired range.
A density close to the theoretical density of the material is desired for a component made from a particulate material, because the mechanical properties of the component improve with increasing density of the compacted particulate. As a result, techniques have been developed to increase the density achieved through the compaction process. These techniques are often focused on multiple level parts, because the geometry of multiple level parts usually make uniform density distribution between the levels more difficult. A discrepancy in density distribution adversely affects the performance of the part and may lead to the formation of cracks in the compaction process.
One technique to improve compaction of multiple level parts is that of a tool rig comprising a die that defines a cavity in conjunction with at least two punches that extend into the cavity. At least one punch is typically actuated through auxiliary motion at some point during the compaction process to move the punch to a different vertical position and thereby direct the flow of the particulate material in the cavity to achieve a more uniform density distribution in the formed part. For parts with many levels, multiple punches may be used and each punch may be separately actuated.
In order to facilitate these actuated punches, designs of prior art tool rigs have relied upon cumbersome designs. A tool rig usually includes platens and/or cylinders to support each punch. Each of these support components must be independently movable to allow each punch to be independently actuated. Likewise, each support component must have an independent source of energy to create independent motion of the support component and its respective punch. Such sources of energy may include connections to hydraulic or pneumatic media. Further, each support component typically has a linear encoder that measures the position and travel of the component, in turn measuring the position and travel of the punch that the component supports.
The requirement of an independent energy supply source for each component that supports an actuated punch has necessitated the design of vertically long tool rigs and presses in the prior art. The vertical length of a press dictated by designs of the prior art is illustrated in European Patent No. EP 0 586 028 B1, issued to the present inventor and others; in PCT Publication No. WO 01/08864 A1, issued to Beane et al.; and in European Patent No. 0 077 897/related U.S. Pat. No. 4,482,307, issued to Schaidl et al. The excessive vertical length of these designs demands deep pits and/or high ceilings in a production facility, results in long tooling stack-ups that are difficult to align and increase set-up time, and yields a deflection that is generally high.
Accordingly, it is desirable to develop a new tool rig that integrates all necessary elements at a substantially reduced height, which provides increased rigidity and maintains good accessibility for set-up.